The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 19, 1989
Filed:
Aug. 02, 1988
James S Hyde, Dousman, WI (US);
Jerzy Gajdzinski, Cracow, PL;
MCW Research Foundation, Inc., Milwaukee, WI (US);
Abstract
An electron paramagnetic resonance (EPR) spectrometer employing a reference arm microwave bridge provides efficient, simultaneous generation of orthogonal I and Q signals. The simultaneous generation is enabled through the use of a field effect transistor (FET) microwave amplifier in the signal arm feeding a balanced quadrature mixer. The I and Q signals are then combined to produce a signal suitable for use as a discriminator in an automatic frequency control (AFC) circuit. An important characteristic of the discriminator signal is that it is independent of the relative phase angle .alpha. between the reference arm and signal arm of the bridge. In a further embodiment, an apparatus is disclosed which computes .alpha. from the I and Q signals, and uses the computed value for .alpha. to extract pure absorption and pure dispersion information from the I and Q signals regardless of the setting of .alpha. in the bridge.